In:
The European Physical Journal B, Springer Science and Business Media LLC, Vol. 93, No. 8 ( 2020-08)
Abstract:
We consider the strongly anisotropic spin-1/2 XXZ model on the sawtooth-chain lattice with ferromagnetic longitudinal interaction J zz = Δ J and aniferromagnetic transversal interaction J xx = J yy = J 〉 0. At Δ = −1∕2 the lowest one-magnon excitation band is dispersionless (flat) leading to a massively degenerate set of ground states. Interestingly, this model admits a three-coloring representation of the ground-state manifold [H.J. Changlani et al., Phys. Rev. Lett. 120 , 117202 (2018)]. We characterize this ground-state manifold and elaborate the low-temperature thermodynamics of the system. We illustrate the manifestation of the flat-band physics of the anisotropic model by comparison with two isotropic flat-band Heisenberg sawtooth chains. Our analytical consideration is complemented by exact diagonalization and finite-temperature Lanczos method calculations. Graphical abstract
Type of Medium:
Online Resource
ISSN:
1434-6028
,
1434-6036
DOI:
10.1140/epjb/e2020-10224-1
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
2020
detail.hit.zdb_id:
1459068-2
detail.hit.zdb_id:
1397768-4
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